[GCM] Add connection factory for creating MCS connections

google_apis/gcm/engine/connection_handler_impl.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef GOOGLE_APIS_GCM_ENGINE_CONNECTION_HANDLER_H_
-#define GOOGLE_APIS_GCM_ENGINE_CONNECTION_HANDLER_H_
+#ifndef GOOGLE_APIS_GCM_ENGINE_CONNECTION_HANDLER_IMPL_H_
+#define GOOGLE_APIS_GCM_ENGINE_CONNECTION_HANDLER_IMPL_H_
 
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
 #include "base/timer/timer.h"
-#include "google_apis/gcm/base/gcm_export.h"
-#include "google_apis/gcm/protocol/mcs.pb.h"
+#include "google_apis/gcm/engine/connection_handler.h"
 
-namespace net{
-class StreamSocket;
-}
+namespace mcs_proto {
+class LoginRequest;
+}  // namespace mcs_proto
 
 namespace gcm {
 
-class SocketInputStream;
-class SocketOutputStream;
-
-// Handles performing the protocol handshake and sending/receiving protobuf
-// messages. Note that no retrying or queueing is enforced at this layer.
-// Once a connection error is encountered, the ConnectionHandler will disconnect
-// the socket and must be reinitialized with a new StreamSocket before
-// messages can be sent/received again.
-class GCM_EXPORT ConnectionHandler {
+class GCM_EXPORT ConnectionHandlerImpl : public ConnectionHandler {
  public:
-  typedef base::Callback<void(scoped_ptr<google::protobuf::MessageLite>)>
-      ProtoReceivedCallback;
-  typedef base::Closure ProtoSentCallback;
-  typedef base::Callback<void(int)> ConnectionChangedCallback;
-
-  explicit ConnectionHandler(base::TimeDelta read_timeout);
-  ~ConnectionHandler();
-
-  // Starts a new MCS connection handshake (using |login_request|) and, upon
-  // success, begins listening for incoming/outgoing messages. A successful
-  // handshake is when a mcs_proto::LoginResponse is received, and is signaled
-  // via the |read_callback|.
-  // Outputs:
   // |read_callback| will be invoked with the contents of any received protobuf
   // message.
   // |write_callback| will be invoked anytime a message has been successfully
   // sent. Note: this just means the data was sent to the wire, not that the
   // other end received it.
   // |connection_callback| will be invoked with any fatal read/write errors
   // encountered.
-  //
-  // Note: It is correct and expected to call Init more than once, as connection
-  // issues are encountered and new connections must be made.
-  void Init(scoped_ptr<net::StreamSocket> socket,
-            const google::protobuf::MessageLite& login_request,
-            const ProtoReceivedCallback& read_callback,
-            const ProtoSentCallback& write_callback,
-            const ConnectionChangedCallback& connection_callback);
+  ConnectionHandlerImpl(
+      base::TimeDelta read_timeout,
+      const ProtoReceivedCallback& read_callback,
+      const ProtoSentCallback& write_callback,
+      const ConnectionChangedCallback& connection_callback);
+  virtual ~ConnectionHandlerImpl();
 
-  // Checks that a handshake has been completed and a message is not already
-  // in flight.
-  bool CanSendMessage() const;
-
-  // Send an MCS protobuf message. CanSendMessage() must be true.
-  void SendMessage(const google::protobuf::MessageLite& message);
+  // ConnectionHandler implementation.
+  virtual void Init(const mcs_proto::LoginRequest& login_request,
+                    scoped_ptr<net::StreamSocket> socket) OVERRIDE;
+  virtual bool CanSendMessage() const OVERRIDE;
+  virtual void SendMessage(const google::protobuf::MessageLite& message)
+      OVERRIDE;
 
  private:
   // State machine for handling incoming data. See WaitForData(..) for usage.
   enum ProcessingState {
     // Processing the version, tag, and size packets (assuming minimum length
     // size packet). Only used during the login handshake.
     MCS_VERSION_TAG_AND_SIZE = 0,
     // Processing the tag and size packets (assuming minimum length size
     // packet). Used for normal messages.
     MCS_TAG_AND_SIZE,
@@ skipping 35 matching lines @@
   // Closes the current connection.
   void CloseConnection();
 
   // Timeout policy: the timeout is only enforced while waiting on the
   // handshake (version and/or LoginResponse) or once at least a tag packet has
   // been received. It is reset every time new data is received, and is
   // only stopped when a full message is processed.
   // TODO(zea): consider enforcing a separate timeout when waiting for
   // a message to send.
   const base::TimeDelta read_timeout_;
-  base::OneShotTimer<ConnectionHandler> read_timeout_timer_;
+  base::OneShotTimer<ConnectionHandlerImpl> read_timeout_timer_;
 
   // This connection's socket and the input/output streams attached to it.
   scoped_ptr<net::StreamSocket> socket_;
   scoped_ptr<SocketInputStream> input_stream_;
   scoped_ptr<SocketOutputStream> output_stream_;
 
   // Whether the MCS login handshake has successfully completed. See Init(..)
   // description for more info on what the handshake involves.
   bool handshake_complete_;
 
   // State for the message currently being processed, if there is one.
   uint8 message_tag_;
   uint32 message_size_;
 
   ProtoReceivedCallback read_callback_;
   ProtoSentCallback write_callback_;
   ConnectionChangedCallback connection_callback_;
 
-  base::WeakPtrFactory<ConnectionHandler> weak_ptr_factory_;
+  base::WeakPtrFactory<ConnectionHandlerImpl> weak_ptr_factory_;
 
-  DISALLOW_COPY_AND_ASSIGN(ConnectionHandler);
+  DISALLOW_COPY_AND_ASSIGN(ConnectionHandlerImpl);
 };
 
 }  // namespace gcm
 
-#endif  // GOOGLE_APIS_GCM_ENGINE_CONNECTION_HANDLER_H_
+#endif  // GOOGLE_APIS_GCM_ENGINE_CONNECTION_HANDLER_IMPL_H_